It's hard to say my favorite of the main series are 6, 7 and 9. So by that logic alone it would seem I prefer the middle to late games. My most hated games of the series are 12 and 8 so that seems to knock it back down. Considering 11 and 14 are mmo's (and I know 11 was not a very fun one) that also brings down the later series.

So overall I-VI were more consistently good but VI-XIV have the stronger in the series (good and bad). If, say, I had to banish half the series out of existence VII would be the deciding factor on what side to keep (whatever it's considered, "old" or "new" I would choose to keep). If Tactics is considered as one of the newer games then I would have to say adios to the older part of the series.